Advanced detection of memory device removal, and methods, devices and connectors

ABSTRACT

Memory devices, connectors and methods for terminating an operation are provided, including a memory device configured to terminate an internal operation such as a programming or erase operation responsive to receiving a signal during removal of the memory device from a connector, such as a socket. The memory device may be configured to generate the removal signal, such as by including a dedicated removal terminal. The memory card may respond to the signal by terminating a programming or erase operation before power is lost. The removal terminal may have a dimension that is different from a dimension of a power terminal. Alternatively, the connector may be configured to generate a signal that causes a host to terminate programming or erase operations prior to memory card removal, such as by including a switch that is actuated when the memory device moves to a pre-power loss position.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.12/478,422, filed Jun. 4, 2009, U.S. Pat. No. 8,189,420, whichapplication is incorporated herein by reference, in its entirety, forany purpose.

TECHNICAL FIELD

Embodiments of this invention relate to memory devices and/or theirconnectors, and, more particularly, in some embodiments, to memorydevices that are normally packaged for insertion and removal in a host,such as a computer or other electronic device using a removable memorydevice.

BACKGROUND OF THE INVENTION

Memory devices, particularly non-volatile memory devices like flashmemory, are commonly packaged in a manner that makes it relatively easyfor users to insert and remove the memory devices from a host, such ashost devices or host systems. Examples of memory devices packaged inthis manner include SD Cards, Micro SD Cards, Flash Memory Cards, and CECards, to name a few. All of these and other memory devices willsometimes be generically referred to herein as “memory cards,” which isintended to refer to any memory device that may be installed in orremoved from a host by means other than soldering or the like. Suchmemory cards frequently use flash memory devices, although other typesof memory devices may also be packaged in this manner.

Generally, such memory cards are inserted into a socket or otherconnector so that a plurality of terminals of the memory card makecontact with respective terminals of the socket or other connector.Various types of connectors for receiving memory cards are in commonuse. One conventional connector is basically just a connector into whichan edge of a memory card containing terminals is pushed by a user. Thecard may be held in position in the connector by the friction resultingfrom the force exerted by the connector terminals against the memorycard terminals. The memory card may subsequently be pulled from theconnector by the user. These types of connectors are known as“push-pull” connectors because of the manner in which they are installedand removed by a user. Devices using push-pull connectors sometimesinclude a plunger, lever or other device that may be actuated by a userto at least partially remove the memory card from the connector.

Another type of memory card connector in common use is known as a“push-push” connector. In a push-push connector, the memory card may bepushed into the connector by a user and then released. When released,the memory card may spring back a short distance but may then be latchedin the connector. The memory card may be at least partially removed byagain pressing in on the memory card, thereby unlatching the memory cardfrom the connector. Once unlatched, the memory card may easily beremoved from the connector. Other types of memory card connectors arealso used, such as memory cards using a universal serial bus (“USB”)connector.

As mentioned above, memory cards frequently use flash memory devices. Asis well-known in the art, flash memory devices are non-volatile memorydevices that typically use a charge stored on a floating or non-floatinggate on each of a large number of transistors to store respective data.The level of the stored charge defines whether the data stored on thetransistor is a logic “0” or a logic “1”, for example. Conventional,flash memory devices may thus be programmed by placing a specific chargeon the floating gates of the transistors. Flash memory cells may beerased by programming all of the memory cells with a specific charge,such as one corresponding to a logic “1.”

Insofar as memory cards generally may be removable from a host at anytime, it may be possible for a user to remove the memory card while aprogramming or erase operation is in process. Unfortunately, the removalof power from the memory card during programming or erase may cause datastored in the memory card to be corrupted. This problem has beenaddressed in various ways. Operating systems, such as various models ofMicrosoft Windows,® provide a user interface to allow a user to indicateto a host that the user intends to remove the memory card from the host.The operating system may respond to the remove indication by causing thehost to apply signals to the memory card that terminate all programmingand erase operations. However, it may be possible for a user to removethe memory card without providing an remove indication to the host,thereby possibly corrupting data stored in the memory card.

With the recent advent of multi-level flash memory devices, which maystore any of 4 or more different charge levels on each floating gate,for example, the problem of data corruption caused by removing memorycards during erase or programming operations may become even moreserious. There is, therefore, a need for a device or method that mayreduce the likelihood of data corruption caused by removing memory cardsduring erase or programming operations or other operations that mayoccur in memory devices that should be completed before the memorydevices are removed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a memory card connector according toone embodiment.

FIG. 2 is a schematic diagram of a memory card and a memory cardconnector according to an embodiment.

FIG. 3 is a timing diagram showing respective removal signals that maybe generated by the memory card and memory card connector of FIG. 2.

FIG. 4 is a schematic diagram of a memory card and a memory cardconnector according to another embodiment.

FIG. 5 is a timing diagram showing a removal signal that may begenerated by the memory card of FIG. 4.

FIG. 6 is another embodiment of a memory card connector that may be usedwith the memory card of FIG. 4.

FIG. 7 is another embodiment of a memory card that may be used with thememory card connector of FIG. 2.

FIG. 8 is another embodiment of a memory card that may be used with thememory card connector of FIG. 4.

FIG. 9 is an embodiment of a memory device that may provide advancenotice of removal from a host.

DETAILED DESCRIPTION

One embodiment of a memory card connector 10 for receiving a memory card20 is shown in FIG. 1. In the embodiment shown, the memory card 20comprises an SD card and the connector 10 comprises an SD cardconnector, but other memory cards may be used in other embodiments usingother types of memory cards and connectors. As is well known in the art,the memory card 20 may be inserted into the connector 10, and ultimatelyreaches a first position where the memory card may be inserted furtheragainst a resilient bias, such as a spring. However, the user maycontinue to insert the memory card until the card has been completelyinserted. When the memory card 20 has been completely inserted, the usermay release the memory card 20 to allow the resilient bias to return thememory card 20 to the first position, which latches the memory card 20in the connector 10.

The memory card 20 may be at least partially removed from the connector10 using the reverse sequence of operations. Specifically, the memorycard 20 may again be pushed into the connector 10 from the firstposition until it has been fully inserted, and may again be released.The memory card 20 may then spring back, thereby unlatching the memorycard 20 in the connector 10. The memory card 20 may then be easilypulled from the connector 10 by the user.

The memory card connector 10 of FIG. 1 further includes a switch 30 thatmay be normally open, but may be pushed to a closed position when thememory card 20 is fully inserted in the connector before being latchedor unlatched. Therefore, the switch 30 will be momentarily closed eachtime after the memory card 20 is inserted and each time before thememory card 20 is removed. The closing of the switch 30 before thememory card 20 has been removed may generate a high priority interruptsignal for a processor (not shown) or other device to cause theprocessor or other device to apply appropriate commands to the memorycard 20 to immediately terminate any ongoing programming or eraseoperations. Insofar as power continues to be applied to the memory card20 for a short period after the switch 30 is closed during removal, thememory card 20 may have sufficient time to respond to the command sothat a programming or erase operation has been terminated by the timepower may be lost.

Although the memory card connector 10 shown in FIG. 1 uses a normallyopen, momentarily closed switch to detect that the memory card 20 hasbeen fully inserted, in other embodiments a normally closed, momentarilyopen switch or some other type of position detector may be used. Also,in other embodiments, the switch 30 may be actuated by a plunger, leveror other device, which, as mentioned above, may be actuated by a user toat least partially remove memory cards from some types of connectors.When the plunger, lever or other device is actuated by a user, theclosing of the switch 30 may provide advance notice of impending removalof memory cards from connectors before power is lost.

The memory card connector 10 of FIG. 1 may prevent inadvertent loss ofdata in any standard memory card that may be configured to be used withthe connector 10. However, in other embodiments, the memory card may bespecially configured to be used with a specially configured connector.For example, as shown in FIG. 2, a memory card 40 is provided with anextra “removal” terminal 44 that is positioned adjacent memory terminals46 normally provided for the memory card 40. The removal terminal 44 maybe shorter than the normal memory terminals 46 so that it does notextend as far from a first edge 48 that is normally first inserted intoa connector. The removal terminal 44 may be coupled to a supply voltageVcc through a resistor 50.

The memory card 40 may be configured for use with a connector 60 thatincludes an extra removal terminal 64 adjacent a set of terminals 66that normally make contact with the memory terminals 46 of the memorycard 40. The removal terminal 64 may be coupled to a particularreference potential, such as ground, through a resistance, such asresistor 68. As is well-known in the art, the terminals 64, 66 arespring loaded against the terminals 44, 46, respectively, and they maycontact the respective terminals of the memory card 20 along arelatively narrow length of the respective memory card terminals. Whenthe memory card 40 has been fully inserted into the connector 60, thepositions of terminals 64, 66 of the connector 60 relative to thepositions of the terminals 44, 46 of the memory card 40 are indicated bythe line 70. In this position, the removal terminal 44 of the memorycard 40 does not make contact with the removal terminal 64 of theconnector 60. As a result, an REMOVAL-C signal provided by the removalterminal 44 of the memory card 40 is at Vcc, and an REMOVAL-S signalprovided by the removal terminal 64 of the connector 60 is at ground.However, when the memory card 40 is latched in the connector 60, theposition at which the terminals 64, 66 of the connector 60 contact theterminals 44, 46 of the memory card 40 are indicated by the line 74. Inthis position, the removal terminal 44 of the memory card 40 may contactthe removal terminal 64 of the connector 60 so that an REMOVAL-C signalprovided by the memory card 40 and an REMOVAL-S signal provided by theconnector 60 are at a voltage V₀. In the embodiment shown in FIG. 2, theresistance of the resistor 50 may be equal to the resistance of theresistor 68 so that the REMOVAL-C and REMOVAL-S signals are at Vcc/2when the memory card 40 has been latched. Therefore, when the memorycard 40 is being removed from the connector 60, the REMOVAL-C andREMOVAL-S signals are as shown in FIG. 3. Specifically, prior toremoving the memory card 40 starting at t₁, the REMOVAL-C signal and theREMOVAL-S signal are at Vcc because the terminal 64 of the connector 60is making contact with the terminal 44 of the memory card 40. However,when the memory card 40 is pushed all the way into the connector 60 tounlatch the memory card 40 from the connector at time t₁, the terminal64 of the connector 60 loses contact with the terminal 44 of the memorycard 40. As a result, the REMOVAL-C signal rises to Vcc, and REMOVAL-Ssignal falls to ground. At t₂, the memory card 40 has been unlatched andis removed to the point that the terminal 64 of the connector 60 losescontact with the terminal 44 of the memory card 40. In this position,the REMOVAL-C signal and the REMOVAL-C signal return to V₀. The V₀ valueof the REMOVAL-S signal between t₁ and t₂ may again generate a highpriority interrupt signal for a processor (not shown) or other device ina host to cause the host to apply appropriate commands to the memorycard 40 to immediately, and relatively safely, terminate any ongoingprogram or erase operations. Alternatively, or in addition, the Vccvalue of the REMOVAL-C signal between t₁ and t₂ may be provided tomemory circuitry 54 in the memory card 40 which may be operable toimmediately terminate all programming or erase operations withoutwaiting for commands from a host. The memory card 40 may then havesufficient time to respond to the REMOVAL-C or commands from the host sothat all programming or erase operations have been terminated beforepower may be lost.

Although the memory card 40 and connector 60 in the embodiment of FIG. 2use resistors 50, 68 forming a resistor divider network, other circuitsmay be used in other embodiments, including circuits that do not consumeas much power as a resistor divider network.

Another embodiment of a memory card 80 and memory card connector 90 isshown in FIG. 4. The memory card 80 and connector 90 are similar to thememory card 40 and connector 60, respectively, shown in FIG. 2.Therefore, in the interest of brevity and clarity, identical componentshave been provided with the same reference numerals, and an explanationof their structure and operation will not be repeated. The memory card80 differs from the memory card 40 by including a removal terminal 84that may be separated from the terminal 44 and by the resistor 50 beingcoupled to the removal terminal 84 rather than to the terminal 44. Also,the connector 90 differs from the connector 60 by connecting theterminal 64 to ground along with the normal signal ground on one of theterminals 66 rather than by connecting the terminal 64 to ground througha resistor 68 as in the embodiment of FIG. 2.

In operation, when the memory card 80 is latched in the connector 90,the terminals of the connector 90 make contact with the terminals of thememory card 80 along the line 74, as previously explained. In thisposition, the terminal 64 of the connector 90 makes contact with theterminal 44 of the memory card 80 so that the terminal 44 may be used asan extra circuit ground terminal for the memory card 80. Insofar as theremoval terminal 84 may be electrically isolated from the groundedterminal 44, the REMOVAL-C signal remains at Vcc. However, since theterminal 64 of the connector 90 is connected to ground, no REMOVAL-Ssignal may be provided in this embodiment. When the memory card 80 ispushed all the way into the connector 90 to unlatch the memory card 80,the terminals of the connector 90 make contact with the terminals of thememory card 80 along the line 70. In this position, the removal terminal84 makes contact with the grounded terminal 64 of the connector, therebypulling the REMOVAL-C to ground. As the memory card 80 is unlatched andis pulled from the connector 90, the terminal 64 of the connector maylose contact with the removal terminal 84 of the memory card 80 therebyallowing the REMOVAL-C signal to return to Vcc. The REMOVAL-C signalresulting from this operation is shown in FIG. 5. Specifically, theREMOVAL-C signal is at Vcc prior to the connector terminal 64 makingcontact with the removal terminal 84 of the connector at t₁. TheREMOVAL-C signal is then pulled to ground until t₂ when the connectorterminal 64 loses contact with the removal terminal 84. The memory card80 may be configured to respond to the active low REMOVAL-C signal byimmediately terminating any ongoing program or erase operation in thememory card 80, such as in order to prevent inadvertent data loss.Insofar as power continues to be applied to the memory card 80 for ashort period, the memory card 80 may have sufficient time to respond sothat a programming or erase operation has been terminated by the timepower may be lost.

Another embodiment of a memory card connector 100 that may be used withthe memory card of FIG. 4 is shown in FIG. 6. The connector 100 isidentical to the connector 60 shown in FIG. 4, but differs in thecircuitry connected to the connector. Specifically, instead ofconnecting the removal terminal 64 of the connector 100 directly toground, the terminal 64 may be connected to ground through a resistor104, and differential inputs of sensing circuitry 108 are connected toopposite ends of the resistor 104. The resistor 104 may have aresistance that may be substantially smaller than the resistance of theresistor 50. Therefore, when the memory card 80 has been fully insertedin the connector 100 so that the secondary removal terminal 84 may be incontact with the removal terminal 64, the memory card 80 actsessentially as a current source. The current source by the memory card80 flowing through the resistor 104 generates a small differentialvoltage that may be sensed by the sensing circuitry 108 to provide anREMOVAL-S signal to a host so it may apply appropriate signals to thememory card 80. Of course, the memory card 80 receives the active lowREMOVAL-C signal, which it allows it to immediately terminate anyongoing program or erase operations. The use of a resistor 104 having aresistance that may be substantially smaller than the resistance of theresistor 50 may have the added advantage of maintaining the removalterminal 44 at substantially zero volts so that the terminal 44 mayserve as an extra ground terminal for the memory card 80. Thus, like theconnector 90, the connector 100 provides the advantage of an extraground terminal, but may also provide an REMOVAL-S signal to the host.As explained above, the REMOVAL-S signal may be used to generate a highpriority interrupt signal for a processor (not shown) or other device ina host to cause the host to apply appropriate commands to the memorycard 80 to immediately, and relatively safely, terminate any ongoingprogram or erase operations. Alternatively, or in addition, theREMOVAL-C signal may be provided to the memory circuitry 54 in thememory card 80 which may be operable to immediately terminate allprogramming or erase operations without waiting for commands from ahost. Insofar as power continues to be applied to the memory card 80 fora short period, the memory card 80 may have sufficient time to respondto commands so that a programming or erase operation has been terminatedby the time power may be lost.

Another embodiment of a memory card 110 that may be used with the memorycard connector 60 of FIG. 2 is shown in FIG. 7. The memory card 110 usesmany of the same components as the memory card 40 of FIG. 2, which havebeen provided with the same reference numerals. The memory card 110differs from the memory card 40 of FIG. 2 by using an removal terminal114 having a length that may be substantially shorter than the length ofthe removal terminal 44 of the memory card 80. In operation, the memorycard 110 operates in the same manner as the memory card 40 when usedwith a push-push memory card connector, like the memory card connector60. However, the memory card 110 may also provide advance notice ofremoval for push-pull memory card connectors, which, as explained above,are simply a connector into which the memory card may be pushed and fromwhich it may be pulled. When the memory card 110 is pulled from theconnector of a push-pull connector, the removal terminal 114 losescontact with the connector removal terminal 64 before the power andground are lost through the memory terminals 46. As a result, theREMOVAL-C signal transitions from whatever voltage is created by theresistor divider formed by the resistors 50, 68 to Vcc, thereby allowingthe memory card 110 to attempt to terminate substantially immediatelyany ongoing program or erase operations before power and ground are lostin the memory card 110. Again, the REMOVAL-S signal may be used togenerate a high priority interrupt signal to cause a host to applyappropriate commands to the memory card 110 to immediately, andrelatively safely, terminate any ongoing program or erase operations.Alternatively, or in addition, the circuitry 54 in the memory card 110may be configured to respond to the active low REMOVAL-C signal byimmediately terminating any ongoing program or erase operation in thememory card 110 in order to prevent inadvertent data loss. Insofar aspower continues to be applied to the memory card 110 for a short period,the memory card 110 may have sufficient time to respond to commands sothat a programming or erase operation has been terminated by the timepower may be lost.

Another embodiment of a memory card 120 that may be used with theconnector 90 of FIG. 4 is shown in FIG. 8. Like the memory card 80, thememory card 120 uses a first removal terminal 124 and a second removalterminal 126. However, the first removal terminal 124 has a length thatmay be substantially shorter than the length of the removal terminal 44,and a third removal terminal 128 may be provided. Both the second andthird removal terminals 126, 128, respectively, are coupled to Vccthrough the resistor 50. Again, the memory card 120 operates in exactlythe same manner as the memory card 80 in the embodiment of FIG. 4 whenused with a push-push memory card connector, like the memory cardconnector 90. However, the memory card 120, like the memory card 110 ofFIG. 7, may provide advance notice of removal when used in a push-pullconnector. When the memory card 120 is inserted in a connector of apush-pull connector, the terminals of the connector make contact withthe removal terminal 124 and the other memory terminals 46 of the memorycard 120 all along the line 74. However, as the memory card 120 ispulled from the connector of the push-pull connector, the removalterminal of the connector loses contact with the primary removalterminal 124 and instead makes contact with the third removal terminal128. The REMOVAL-C signal provided to the memory card 120 thentransitions from Vcc to ground. The REMOVAL-C signal thus has the samecharacteristics as when the memory card 120 is being removed from apush-push connector to cause the second removal terminal 126 to makecontact with the terminal 64 of the connector 90. As with otherembodiments, the circuitry 54 in the memory card 110 may be configuredto respond to the active low REMOVAL-C signal by immediately terminatingany ongoing program or erase operation in the memory card 110 in orderto prevent inadvertent data loss. As a result, programming and eraseoperations may be terminated before power has been lost from the memorycard 120.

Although the memory card 120 has been explained in the context of beinginserted in a push-push connector like the connector 90, it may also beused with other types of push-push connectors as well as push-pullconnectors. For example, the memory card 120 may be used with theconnector 100 of FIG. 6 since, as far as operation in a push-pushconnector is concerned, the memory card 120 may be identical to thememory card 80. In such case, the connector 100 provides the REMOVAL-Ssignal at the same time that the memory card 80 provides the REMOVAL-Csignal, as explained above with reference to FIG. 6. Although the memorycard 40 and connector 60 in the embodiment of FIG. 2 use resistors 50,68 forming a resistor divider network, other circuits may be used inother embodiments, including circuits that do not consume as much poweras a resistor divider network. However, the resistor divider networkused in the embodiment of FIG. 2 only consumes power for only a shortperiod during memory card removal.

Another embodiment of a memory device 130 that may provide advancenotice of removal from a host is shown in FIG. 9. The memory device maybe in the form of a familiar nonvolatile memory device sometimes knownas a “USB drive,” which includes a housing 134 having a universal serialbus (“USB”) connector 136 projecting from the housing 134. However, theembodiment may also be applicable to other types of removable memorydevices, such as SD memory cards. The device 130 may also include adetector 140 that may sense when the device 130 is about to be removedfrom a host, such as a personal computer or other electronic device. Inone embodiment, the detector 140 may be an externally sensitivecapacitive detector, such as one in which the capacitance betweencapacitor plates may be altered when a user grasps the memory device130. In other embodiments, the detector 140 may be a mechanical forcedetector, such as one that senses pressure applied to the housing 134 bya user before removing the memory device 130 from a host. In still otherembodiments, the detector 140 may be an externally optical detector,such as one that senses a change in the intensity or othercharacteristics of ambient light as the housing 134 is grasped by auser. Other embodiments may use other types of detectors.

Although the present invention has been described with reference to thedisclosed embodiments, persons skilled in the art will recognize thatchanges may be made in form and detail without departing from theinvention. For example, the removal terminals in the various embodimentsof a memory card have dimensions in a first direction that isperpendicular to the edge of the card that are different from dimensionsof other terminals in the first direction. However, in otherembodiments, a removal terminal of a memory card may be identical toother terminals of the memory card. Instead, a point of contact betweena removal terminal of the connector and the removal terminal of thememory device may be offset in the first direction from respectivepoints of contact between other terminals of the connector andcorresponding terminals of the memory device. Such modifications arewell within the skill of those ordinarily skilled in the art.Accordingly, the invention is not limited except as by the appendedclaims.

We claim:
 1. A connector comprising: a plurality of memory terminals;and a memory removal detector configured to generate a signal before amemory has been removed from the connector, wherein the memory detectorcomprises: at least one removal terminal; and a differential amplifierhaving respective first and second differential inputs coupled across aresistance.
 2. The connector of claim 1 wherein the resistance comprisesa first resistance, and the memory removal detector further comprises asecond resistance, wherein the second resistance is coupled between theat least one removal terminal and a voltage.
 3. The connector of claim 2wherein the first resistance is substantially smaller than the secondresistance.
 4. The connector of claim 3 wherein the at least one removalterminal voltage being substantially zero.
 5. The connector of claim 4wherein the at least one removal terminal provides an additional groundterminal for the memory.
 6. A connector comprising: an electrical powerterminal; and a memory removal detector configured to detect movement ofa memory while the electrical power terminal is connected to a powersource and provide a removal signal responsive to the movement of thememory and in advance of removal of the memory from the connector. 7.The connector of claim 6 further comprising memory circuitry, whereinthe memory circuitry is configured to halt an operation responsive, atleast in part, to the removal signal.
 8. The connector of claim 7wherein the operation is a programming or erase operation.
 9. Theconnector of claim 7 wherein the operation is halted in the memory. 10.The connector of claim 7 wherein the operation is halted in a connectedprocessor or host.
 11. The connector of claim 6 wherein the memoryremoval detector is configured to detect the movement of the memorybased at least in part on a state of contact between a removal terminalof the memory and the electrical power terminal.
 12. The connector ofclaim 6 wherein the memory removal detector includes a switch, and thememory removal detector is configured to detect the movement of thememory based at least in part on the switch being closed by the movementof the memory.
 13. The connector of claim 6 wherein the removal signalis a high priority interrupt signal.
 14. A connector, comprising: aplurality of memory terminals; and a memory removal detector configuredto generate a signal before a memory has been removed from theconnector, wherein the memory detector comprises: at least one removalterminal; a first resistance coupled between the at least one removalterminal and a voltage; and a second resistance coupled between the atleast one removal terminal and a reference potential.
 15. The connectorof claim 14 wherein the reference potential is ground.
 16. The connectorof claim 14 wherein the first resistance and the second resistance areequal.
 17. The connector of claim 14 wherein the first and secondresistance form a resistor divider network.
 18. The connector of claim14 wherein the at least one removal terminal is shorter than theplurality of memory terminals.
 19. The connector of claim 14 wherein thesignal is provided to memory circuitry in the memory to immediatelyterminate all operations without waiting for commands from a host. 20.The connector of claim 19 wherein the operations comprise program orerase operations.